Base event JSON encoding decoding check can fail for any float values.

In MDL-43175, the comparison of event data with its decoded equivalent was relaxed so that floats which happened to be whole numbers would not throw unwanted debugging messages, but this comparison can fail for any float.

To replicate, add the following to lib/tests/event_test.php in the test_problematic_events() function:

// Check that other float numbers do not trigger debugging messages.

        $event8 = \core_tests\event\unittest_executed::create(array('courseid'=>1, 'context'=>\context_system::instance(),

                'other' => array('starttime' => microtime(true), 'wholenumber' => 90.0000, 'numberwithdecimals' => 54.7656, 'sample' => 1)));

        $event8->trigger();

        $this->assertDebuggingNotCalled();

The PHP documentation says "do not compare floating point numbers directly for equality" (http://php.net/manual/en/language.types.float.php)